IgG4-related disease presenting with multiorgan involvement

Immunoglobulin G4-related disease (IgG4-RD) is a rare fibroinflammatory immune-mediated condition which can affect multiple organ systems and form mass-like lesions. Initial presentation can mimic other diseases such as pancreatic malignancy when there is pancreatic involvement or tuberculosis (TB) when there are pulmonary lesions or hypertrophic pachymeningitis (HP). Here, we report a novel case of IgG4-RD presenting as bilateral subdural haematomas with additional findings. Our patient is a male who presented with headaches and blurred vision. Physical examination showed disconjugate gaze with a fixed pupil. Trauma survey radiologic imaging revealed a pancreatic mass concerning for malignancy. Subsequent workup found hypophysitis with optic chiasm compression and hypopituitarism, mediastinal lymphadenopathy and HP. Laboratory values showed an elevated serum IgG4 level and latent TB. Our case adds to the existing IgG4-RD literature by highlighting a unique presentation. It is important to maintain it on the differential diagnosis especially in multisystemic presentations with competing diagnoses.